The present invention relates to a waterproof connector wherein a waterproofing gel through which a terminal passes is provided inside a connector housing, and relates in particular to a waterproof connector wherein a preferable sealing portion is formed when a gel is penetrated and the generation of gel chips is prevented.
Conventionally, grease is employed in certain cases to seal connector housings and electric wires led therefrom. However, high temperatures adversely affect and reduce the viscosity of grease, and when this occurs, the grease will leak from a sealed portion, thereby such a seal unstable. In addition to grease, an epoxy resin adhesive may be used for this type of sealing structure. But in this case, although a reliable sealing structure can be provided, after the adhesive has hardened, the insertion or re-insertion of a electric wire is impossible.
To resolve this problem, a waterproof connector is disclosed, in, for example, in Japanese Patent No. 2763300. As is shown in FIG. 12, a frame-shaped stopper 5 is projected inward along the inner periphery of an opening 3 at one end of a quadrilateral rear holder 1, in which openings are formed in parallel opposing ends. A plate-shaped base 7, in which a grid-shaped pattern of multiple terminal through holes 9 is formed, is inserted into the rear holder 1 and is positioned so that it contacts the stopper 5, which retains the base 7 and prevents it from slipping out through the opening 3.
Subsequently, a mat-shaped sealing member (gel) 13 is inserted through another opening 11 into the rear holder 1 wherein the base 7 is retained. As is shown in FIG. 13, the outer peripheral faces of the gel 13 closely contact the inner faces of the rear holder 1, and its forward surface is held against the rear of the base 7 by a protrusion 15. Then, as is shown in FIG. 14, the rear portion of a housing 17 is fitted into the rear holder 1 through the opening 11. As is shown in FIG. 15, for the insertion of terminals, openings 19, which communicate with terminal chambers, are formed in the rear portion of the housing 17. These openings 19, each of which is arranged opposite a corresponding terminal through hole 9 in the base 7, are separated from the terminal through holes 9 by the intervening gel 13.
To employ the thus assembled waterproof connector, terminals 23, connected to electric wires 21, are inserted into the terminal through holes 9 in the exposed face of the base 7 in the rear holder 1. As the terminals 23 are inserted, they break the surface of and pass through the gel 13 into the openings 19 and enter the terminal chambers in the housing 17, wherein they are retained. During this process, as the electric wires 21 pass through the gel 13, some of the gel 13, which adheres closely to the outer circumferences of the electric wires 21, is carried into the housing 17 and seals the gaps between the electric wires 21 and the housing 17.
Use of this waterproof connector forestalls the possibility that grease will leak out at high temperatures, which can occur if grease is used, and ensures that terminals can be removed and re-inserted, which is impossible when an epoxy adhesive is employed.
However, when the related waterproof connector is used, and the rear holder is fitted over the rear portion of the housing, the gel is sandwiched between the rear holder and the housing, and compressed. As a result, resistance to the passage of the terminals is increased, and since then the electric wires may be bent or the terminals may not be able to break through and penetrate the gel, deterioration of the operational efficiency of the terminal attachment occurs. Further, when there is excessive resistance to the passage of the terminals, the terminals may rub against and displace gel, and incomplete-sealing may occur at the areas penetrated by the terminals.
In addition, since the gel closely contacts all the surface around the circumferences of the terminal insertion openings, when, as is shown in FIG. 15, a terminal 23 is pressed against the gel 13 until it breaks the surface and passes through it, part of the gel 13, on the through hole exit side, that closely contacts the inner wall 25 can not recover and is extended and carried into the opening 19 with the terminal 23. This extended portion 13a is cut off, and forms chips 13b, as is shown in FIG. 16, and the chips 13 are carried into a terminal chamber 27 with the terminal 23. In this state, when this connector is coupled with another connector, the chips 13b may work in between the contact points of the terminals, and cause a conductive failure.